CST4 antibody is a research tool designed to target cystatin-S (CST4), a member of the cystatin superfamily of cysteine protease inhibitors. Cystatin-S is primarily secreted by salivary and lacrimal glands, playing roles in maintaining oral health, regulating inflammatory responses, and modulating enzymatic activity in biological fluids. The CST4 gene encodes a 14-16 kDa protein that binds to and inhibits cathepsins, enzymes involved in protein degradation, immune regulation, and tissue remodeling. Dysregulation of CST4 has been implicated in conditions like Sjögren’s syndrome, periodontal disease, and certain cancers.
CST4 antibodies are typically produced in hosts like rabbits or mice using recombinant CST4 proteins or synthetic peptides. They enable detection of endogenous CST4 in immunoassays (e.g., Western blot, ELISA, immunohistochemistry) and are valuable for studying its expression patterns, interactions, and functional roles. Some studies explore CST4 as a potential biomarker for tumor progression or autoimmune disorders due to its altered secretion in pathological states. Commercial CST4 antibodies often undergo validation for specificity, sensitivity, and cross-reactivity across species (human, mouse, rat). Researchers utilize these antibodies to investigate CST4’s involvement in protease balance, mucosal immunity, and disease mechanisms, supporting both basic research and diagnostic applications.